Any reason not to use a capacitor on the Rx?

[Bobmic]

I was thinking to add a capacitor (or maybe more ) in parallel to my receiver's voltage input to add another layer of protection.
Even though I am using BEC's on most of my planes I was thinking of adding capacitors a while ago and have many reasons why it should be a good thing but can not think of why not... beside the fact that I haven't seen many who are using this method.
Almost all of my BECs are the Turnigy 5Amp not the CC 10Amp, although I have never had a problem with them I might guess that CC might have a tighter QC although I am not so sure.

Thank you
B.

[piker]

I haven't had to add any extra suppression to anything for years, but I did, at one point have to run the servo lead (with BEC) from a CC 60A controller, though a ferrite ring to eliminate some interference.  Solved the problem completely.

As you say, my understanding is that controllers have caps built in to suppress back EMF... at least that's my understanding.

Robert

[bfeist]

Are you expecting short bursts of high loads that the BEC won't be able to handle? Personally, I wouldn't add circuitry to existing circuitry, it adds variables. If you're not confident just spend the money on a 10A dedicated BEC. For my Revolver (arguably the highest BEC loads of any of my planes) the built in BEC in the ICE 100 works perfectly. Running it at 6V too.

Ben

[Bobmic]

Rob - I was referring to receiver input voltage, the capacitor will only dampen any current spikes that might cause a brownout. This will be more for models that have retracts and a higher number of servos or maybe high torque servos.

[MarcV]

Well Spektrum sells a capacitor to prevent receiver brownouts.
http://www.spektrumrc.com/Products/Default.aspx?ProdID=SPM1600

But adds "This Voltage Protector is not intended for Aircraft use."

Anybody know why?

Marc

[Ededge2002]

The spektrum brown out issue has been a short fall of the design since early on. The capacitor would give a LITTLE added power but any sustained load would diminish the voltage it provided very quickly.   
Spektrum has worked hard to minimize the low voltage troubles within its genuine receivers but I always wonder how much the clones have accomplished in this.
I have used the CC10 set to 6v with spektrum and never had a brown out or suspicious crash. Enough for me to trust it in my mind.

[pmackenzie]

Well Spektrum sells a capacitor to prevent receiver brownouts.
http://www.spektrumrc.com/Products/Default.aspx?ProdID=SPM1600

But adds "This Voltage Protector is not intended for Aircraft use."

Anybody know why?

Marc

Because the car guys are the only ones gullible enough to fall for this?

As Ed pointed out, the cap is just too small to make much difference. (IMO)

If Spektrum truly thinks there should be a cap on the battery rails, they should build it into the receiver.

Pat MacKenzie

[Tom]

I'm not sure a capacitor alone will help much.  A large capacitor capable of helping with brownouts would draw such a large inrush current it may damage the BEC and a small one won't store enough energy to keep the voltage up. If you're having a problem with one of your planes I can help you set up a circuit with a big capacitor using a circuit to slow charge the cap to prevent overloading the BEC.  We can try a super capacitor!  I've been looking for an excuse to try one.

[pmackenzie]

Saw this yesterday - much better solution since it would actually work

http://www.innov8tivedesigns.com/product_info.php?cPath=22_24_146&products_id=1154

[Ededge2002]

"Innovative" solution!  I would have thought it would be LiFe based but still a neat solution.
Thanks for posting Pat